There have been proposals to make portable electronic devices such as personal computers and tablet type terminals incorporate radio devices for receiving analog television broadcasts, data broadcasts, mobile data broadcasts, and the like so as to allow to receive broadcast signals or data from the radio devices and display them on displays or to store them in memories.
As an antenna used in a radio device for broadcast reception, an antenna apparatus is generally used, which allows selection between a state in which an antenna element is retracted into the housing and a state in which the antenna element extends from the housing. An antenna apparatus of this type allows the user to view and listen to broadcasts while selectively using the use patterns of the antenna in accordance with surrounding conditions.
The above conventional antenna apparatus, however, has the following problem to be solved. That is, using the antenna element while keeping it outside the housing can easily obtain good characteristics. When using the antenna element while accommodating it in the housing, since the antenna element receives the influences of the ground portion on a printed wiring board set in the housing and the like, the resonance frequency shifts to a value lower than a desired value. This may lead to a deterioration in reception performance.